Performance assessment of a low-cost UV/activated carbon-CuFe2O4 photocatalysis system for micropollutants removal from secondary effluent.

To address the limited micropollutant removal efficiency of conventional wastewater treatment plants (WWTPs), an ultraviolet (UV)/activated carbon (AC)-CuFe2O4 photocatalytic system was developed and evaluated under UV-C irradiation (λ = 254 nm). AC-CuFe2O4 was prepared using a co-precipitation/calcination method. The UV/AC-CuFe2O4 (1:2) system achieved removal efficiencies above 94 % for six representative micropollutants (i.e., atrazine (ATZ), 17α-ethinylestradiol (EE2), carbamazepine (CBZ), bisphenol A (BPA), alachlor (ALA) and diuron (DIR)) from secondary effluent within 20 min and without the addition of external oxidants, outperforming the UV, UV/AC and UV/CuFe2O4 system. UV/AC-CuFe2O4 photocatalysis showed good adaptability under both acidic and alkaline conditions, and maintained high removal efficiency after five reuse cycles. Superoxide radicals (•O2-) was determined to be the key reactive species, while •OH, e- and h+ also contributed to the removal. The electrical energy per order (EE/O) values for the six micropollutants ranged from 3.0 to 5.2 kWh/m3. Combined Three-dimensional excitation-emission matrix (3D-EEM) and UV254 analyses showed effective removal of bulk organics during treatment, with humic-like substances reduced by 51 % and UV254 absorbance decreased by 39 %, indicating removal of aromatic and unsaturated compounds. These findings highlight the potential of combined UV/AC-CuFe2O4 photocatalysis as a robust and sustainable technology for advanced wastewater treatment applications.